131. 88 Method of Simple Instruments 132. Choice of stations 88 133. Time of readings 89 134. Details of the method 89 135. Records 91 Method of Ecograph Batteries 136. 92 Expression of Physical Factor Results 137. The form of results 94 Factor Records 138. 94 Factor Curves 139. Plotting 95 140. Kinds of curves 96 141. Combinations of curves 96 142. The amplitude of curves 98 Factor Means and Sums 143. 98 CHAPTER III. THE PLANT STIMULUS AND RESPONSE General Relations 144. The nature of stimuli 100 145. The kinds of stimuli 100 146. The nature of response 101 147. Adjustment and adaptation 102 148. The measurement of response 103 149. Plasticity and fixity 104 150. The law of extremes 105 151. The method of working hypotheses 106 Hydroharmose Adjustment 152. Water as a stimulus 107 153. The influence of other factors upon water 107 154. Response 108 155. The measurement of absorption 109 156. The quantitative relation of absorption and transpiration 111 157. Measurement of transpiration 113 158. Field methods 114 159. Expression of results 116 160. Coefficient of transpiration 117 Adaptation 161. Modifications due to water stimuli 118 162. Modifications due to a small water supply 118 163. The decrease of water loss 118 164. The increase of water supply 121 165. Modifications due to an excessive water supply 121 166.